Welcome to the data portal of meereisportal.de

The data and image archive of meereisportal.de provides sea ice data of the Arctic and Antarctic. In addition to
graphic representations of the underlying verified data and derived data products it is also possible to download
the information for further processing.

The selection menu allows an adequate filtering of all map and data information stored in the archive. The navigation
in the selection menu is orientated from left to right. It is not possible to offer data for all regions and all
temporal resolutions. Thus, only the available choices for the selected combinations are shown.

Welcome to the data portal of meereisportal.de

The data and image archive of meereisportal.de provides sea ice data of the Arctic and Antarctic. In addition to
graphic representations of the underlying verified data and derived data products it is also possible to download
the information for further processing.

The selection menu allows an adequate filtering of all map and data information stored in the archive. The navigation
in the selection menu is orientated from left to right. It is not possible to offer data for all regions and all
temporal resolutions. Thus, only the available choices for the selected combinations are shown.

Airborne data

Here you find all sea ice data that has been collected from different aircraft based measurements in the data base
PANGAEA since 1995. The sea ice data is organized in tabular form and distinguished by measurement method (AEM:
Airborne Electromagnetic Measurement, LiDAR: Light detection and ranging).

Antarctic data

Autonomous measurements of sea ice properties

Buoys, or more generally speaking "ice tethered platforms" that perform autonomous measurements of physical
properties of sea ice, snow, and the uppermost ocean are one of the main instruments to collect time-series data
sets from the remote polar regions. Here we present data, metadata, and results from our buoys drifting on Arctic
and Antarctic sea ice.

Other buoys

International Program on Antarctic Buoys (IPAB): https://www.ipab.aq/ (note that this page is currently under revision for
updates).

In addition, all data from active and past Sea Ice Mass-Balance Buoys, which are under administration of the Cold
Regions Research and Engineering Laboratory (CRREL) may be found here:
http://imb.erdc.dren.mil/newdata.htm

Note: If you are aware of other buoy data collections, please send us a message, we would be happy to link them here,
too.

Manual measured data

Here you find all sea ice data that has been collected from different manual measurements in the data base
PANGAEA since 1991. The sea ice data is organized in tabular form and distinguished by measurement method (in-situ, radiation, standardized visual observation ASPeCT /ASSIST).

Echosounder Data

This data set consists of moored Upward Looking Sonar (ULS) data from 14 stations in the Weddell Sea. Parameters in
the processed data files are water pressure, water temperature, draft, and a flag to indicate if the instrument is situated
under ice. Raw data files contain additional parameters. These data were contributed by the Alfred Wegener
Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany, in 1999. Data are available via FTP.

Models

Introduction

The Coupled Model Intercomparison Project (CMIP) is a framework for coordinated climate simulations conducted with
Earth System Models (ESMs) and General Circulation Models (GCMs). The most recently completed phase of the project
(2010-2014) is CMIP5, which promotes a standard set of model simulations in order to understand the response of the
climate system to changes in the external forcing. To this overarching purpose, CMIP5 allows scientists to

evaluate how realistically the models simulate the recent past (1861-2005)

analyze projections of future climate change on two time scales, near term (out to about 2035) and long term (out
to 2100 and beyond)

understand some of the factors that cause differences in model projections, including quantifying some key feedbacks
such as those involving clouds and the carbon cycle.

Description

This page collects the output of 34 climate models, providing projections of sea ice concentration in the Arctic and
Antarctic regions for the period 2010-2100. In particular, the sea ice concentration has been averaged over three time
slices of 30 years each: 2010-2039, 2040-2069 and 2070-2099. The maps are available for the months of February, when
sea ice extent and area are near its maximum in the Arctic and minimum in the Antarctic, and September, when sea ice
extent and area are minimum in the Arctic and maximum in the Antarctic. This selection is performed in accordance with
IPCC 2013 [1].

The projections are formulated for three different RCP (Representative Concentration Pathways) scenarios. These are three
greenhouse gas concentration trajectories adopted in the fifth IPCC Assessment Report (AR5), in 2013[2]. The three RCPs,
RCP2.6, RCP4.5 and RCP8.5, are named according to the increase of radiative forcing from anthropogenic emissions of
well-mixed greenhouse gases in the year 2100 relative to pre-industrial values (+2.6, +4.5, and +8.5 W/m2,
respectively)[3].

For each map, the sea ice extent and area are included. Furthermore, the observed reference climatological sea ice
extent line (15%) is mapped for the period 1981-2010 (NSIDC). This allows an immediate visual comparison of the
modelled state with the current sea ice condition. The 15% contour line of the modelled sea-ice concentration field
is also drawn in the maps.

The models differ both, in their complexity and in their spatial resolution. For this reason, the model results differ
sometimes substantially. However, a transition towards a September ice-free Arctic for the highest-emission scenario
RCP 8.5 occurs across all the models [4]. Most of the maps show a sea ice concentration which is the average of different
model runs (ensemble members), for the same RCP scenario. The number of the ensemble members is reported underneath
the color bar, together with the model name.

Documentation

A complete documentation for the models can be found at the es-doc
(Earth System Documentation), including references.Specifically, use the following search criteria Project/MIP Era:
CMIP5, Document Type: Model.

Technical aspects

Some technical aspects concerning the maps are reported in the following points:

The models ACCESS1.0, ACCESS1.3, BNU-ESM, GFDL-CM3 and GFDL-ESM2M are interpolated to a regular lon/lat grid, for visualization purposes.

The land masks for the models CanESM2, CSIRO-MK3.6.0 and EC-EARTH are not perfectly matching the sea ice concentration variable. However, these were the best land masks available for these models.

The maps related to the models CSIRO-MK3.6.0, GISS-E2-H, GISS-E2-H-CC, GISS-E2-R and GISS-E2-R-CC do not include the 15% contour line of the model.

Method

There are different methods to measure sea ice. This area of the data portal is structured accordingly. The sea ice
data is organized by the different methods which can be accessed via the upper navigation bar.

Sea ice concentration

The data, maps and sea ice analyses of the Arctic and Antarctic available for download are based on the information
of the satellite radiometers mentioned below. Measurements of the satellite radiometer AMSR-E range from June 19th,
2002 until September 30th, 2011. On Oct 4, 2011, measurements of AMSR-E stopped.

AMSR-E‘s successor AMSR2 was successfully deployed to orbit on May 18th 2012. Since August 1st, 2012 AMSR2 has been
sending microwave data from which daily sea ice concentrations are derived. Sea ice concentration based on SSMIS has been available from
October 1st, 2011 up to today. Data of AMSR2 is of higher quality than SSMIS data. On meereisportal.de, SSMIS data is
therefore only used to fill data gaps of AMSR2. The sensor used to define sea ice concentrations is recorded in the
name of the respective daily file.

The sea ice concentration data is written in HDF-format. The coordinates and land mask files needed for further
processing can be downloaded here and will be needed only once per hemisphere.

All sea ice concentration data of the Arctic and the Antarctic, including data until June 19th 2002, (HDF-format)
from the University of Bremen (Institute of Environmental Physics) can
be accessed here. This site includes data
sets for Arctic, Antarctic and, in a higher temporal resolution (3.125km), a number of regional maps.
They use a polar stereographic projection with equal area at 70° latitude. The geographical coordinates of the pixels are given in separate files
are in this file for Arctic
and in this file for Antarctica.

If there are any questions or difficulties, please do not hesitate to contact info@meereisportal.de.
We are pleased to help and steadily improve our offer.

Furthermore, downloads of daily updated KMZ files usable for Google Earth depictions are available for the
Arctic and
Antarctic.

Soon, also KMZ- and GeoTIFF-files will be available for download for the entire period via the selection menu.

Besides the daily data sets, monthly data sets can be downloaded as well. Development, validation and improvement of
the evaluating algorithms were performed in connection with the EU project DAMOCLES (Developing Arctic Modeling and
Observing Capabilities for Long-term Environmental Studies). Sea ice extent was determined by direct satellite
measurements and the so-called “ARTIST” sea ice algorithm. It has been used and validated in many scientific
studies.

We assume no liability for any of the provided data available for downloaded.

Sea ice concentration is represented in the maps by a uniform color scale: White represents a sea ice concentration
of 100%, dark blue marks the regions with the lowest sea ice concentration. According to standard definition , sea
ice extent is the continuous area for which a sea ice concentration of at least 15 % is measured.

All graphs need to be cited according to the rules listed in the "Terms of Use".

Sea ice extent/area

For over 30 years sea ice coverage has been determined based on satellite data. It is normally defined by the sea ice
extent, sea ice area in square meters and sea ice concentration (more information
here).

The data portal provides time series of the monthly mean of sea ice extent and area in the Arctic and Antarctica for
January to December since 1979. Moreover, the anomalies of the monthly mean of the sea ice extent in relation to the
long-term mean are available for January to December from 1981 to 2010.

Sea ice thickness (CryoSat-2)

Data of sea ice thickness is derived from the CryoSat-2,
satellite of the European Space Agency (ESA). Launched in 2010, the polar-orbiting CryoSat was developed to measure
thickness variations of polar ice masses, including glaciers and the great inland ice sheets of Greenland and
Antarctica. Currently, changes are especially apparent in the Arctic sea ice. Thus, a major aim of the CryoSat
mission is the determination of Arctic sea ice thickness. It is being planned to offer comparable data for the
Antarctic.

With the CryoSat-2 radiometer the small portion of the ice/snow cover above the sea surface (surface elevation or
freeboard) is measured and then transformed into ice thickness based on a several assumptions. The Alfred Wegener
Institute, Helmholtz Centre for Polar and Marine Research works together with ESA in a collaborative project on the
accuracy of the sea ice thickness data. The first freeboard and sea ice thickness maps resulting from this project
are now available on this website: Deutsches CryoSat
Projektbüro.

Data sets available for download here are only an outlook on the quality expected in the finalized data (Disclaimer). The data is also available via
FTP ↗. All relevant information about the AWI
CryoSat-2 “Sea Ice Thickness Data Product” is summarized in the following document.

Daily Thickness of Thin Sea Ice Maps (SMOS)

The thickness of thin sea ice is daily retrieved from observations of the L-band microwave sensor SMOS (Soil Moisture
and Ocean Salinity) in the incidence angle range of 40° to 50°, horizontal and vertical polarization.

Thin sea ice occurs during the freezing season. In the melting season, the thickness of sea ice is highly variable.
In addition, the emissivity properties change due to the wetness of the surface and occurrence of melt ponds in the
Arctic. Therefore, thickness data are calculated only during the freezing season, that is from October to April in
the Arctic and from March to September in the Antarctic. During the melting season, the procedure does not yield meaningful results.

As the resolution of SMOS at the used incidence angle range is about 40 km, only larger regions of thin ice will be
retrieved correctly. The rim of thin ice shown in many cases not necessarily indicates thin ice, but can also be
caused by the smearing effect (convolution) of the low resolution.

This service has been developed in the framework of the EU project SIDARUS.
After completion of the SIDARUS project end 2013, the service is continued on a best effort base in the context of
the Polar View and of the Arctic Regional Ocean Observing System (Arctic ROOS). For more information visit the website
of University of Bremen. Further SMOS
data are also available here at Hamburg University.

The procedure and validation efforts are described in Huntemann et al. (2014)
However, no warranty is given for the data presented on these pages.

Weekly Sea Ice Thickness Maps based on CryoSat-2/SMOS Data Fusion

The combination of CryoSat-2 and SMOS data sets can be used to achieve improve sea ice thickness information and the
update rate of Arctic wide maps. This is based on the fact that CryoSat-2 is designed for ice thickness retrieval
for thicknesses above 1 meter while SMOS delivers accurate thin ice thickness information.

The combination of both datasets is based on a statistical approach (optimal interpolation), which merges weekly
information from CryoSat-2 and SMOS from the Alfred Wegener Institute based on the
respective uncertainties for different thickness classes. The joint product was developed within the ESA project SMOS+ Sea Ice.

A detailed algorithm description can be found here. An overview can be found in the publication of Kaleschke et al. (2015). The use of this product is based on similar terms and conditions than
the CryoSat-2 data product (Disclaimer)

Background

Sea ice drift vectors deduced from satellite remote sensing offers valuable opportunities to study the dynamical
processes of sea ice and its role in the Arctic climate system. In recent years, a number of sea ice drift
products came to be available. The products have different advantages and weaknesses depending on sensors,
frequencies, and algorithms used to derive the drift vectors. The temporal coverages are also different due to
the different operational period of the satellite-borne sensors. In some cases, users find large differences of
the ice drift estimates from different products and hesitate over which product to choose. These differences
should be taken into account as uncertainties of the drift vectors of each product. Here we provide
uncertainty estimates of respective ice drift products for practical use.

What user find on the website?

Users can find figures and respective data files in NetCDF-format of the monthly mean sea ice drift of each
product and their corresponding uncertainty and bias maps.

Description of the data

This site provides uncertainty and bias estimates of monthly mean ice drift vectors from various products in the
Arctic Ocean. The original sea ice drift vectors are provided from OSISAF (OSI-405), Ifremer (CERSAT),
National Snow and Ice Data Center (Polar Pathfinder Daily 25 km
EASE-Grid Sea Ice Motion Vectors, version 2) and Noriaki KIMURA at the
National Institute of Polar Research, Japan. The uncertainties of respective products
are assessed by high-resolution SAR data provided from
Jet Propulsion Laboratory (Kwok et al., (2000)) based on the method described in
Sumata et al. (2015).
Note that only the two datasets (NSIDC and Kimura) give a full seasonal coverage. For other products summer ice
drifts are not available due to limitations of sensor capability and the frequency used. There are additional
missing months in some products due to technical problems of the sensors used.

The OSI405-b product combines the single-sensor products to take the advantage of the different quality statistics of the
different products and to compensate for missing data in each product. The product is continuously updated
to exploit available satellite data with different operational periods. The latest version is OSI405c, which
provides summer ice drift map as well as winter maps with uncertainty estimates.

The OSI405-multi product combines the single-sensor products to take advantage of the different quality statistics of the
different products and to compensate for missing data in each product. The merging method of the single-sensor
products is described in Lavergne and Eastwood (2010).

The OSI405-amsr product is a single-sensor product derived from Advanced Microwave Scanning Radiometer of the Earth Observation
System (AMSR-E). A distinctive feature of the product is that a sequence of remotely sensed images is
processed by the Continuous Maximum Cross-Correlation (CMCC) method, which builds on the Maximum
Cross-Correlation (MCC) method but relies on a continuous optimization step for computing the motion
vector (Lavergne et al., 2010).

The CERSAT-merged product is obtained from the combination of SSM/I 85GHz H/V brightness temperature maps and
QuikSCAT backscatter map. The algorithms used to derive each single-sensor product are the same with that
for CERSAT-amsr, and the merging process is described in Girard-Ardhuin et al. (2008).

The CERSAT-amsr product is a single-sensor product derived from Advanced Microwave Scanning Radiometer
of the Earth Observation System (AMSR-E). The algorithm used to derive CERSAT-amsr ice motion is the MCC method described in
Ezraty et al. (2007). The ice motion is estimated from the displacement for 2, 3, and 6 day lags. The 6 day lag is particularly
suitable to capture small displacements which cannot be detected by shorter time lags.

The Kimura Product provides ice motion data from winter as well as summer. The winter ice drift
(from December to April) is calculated from brightness temperature maps of AMSR-E 89
GHz H/V polarization channels, whereas the summer ice drift (from May to November) is obtained from
those of 18.7 GHz channels. The algorithm used to deduce ice motions is the improved MCC method
described in Kimura and Wakatsuchi (2000, 2004).

NSIDC (Polar Pathfinder Daily 25 km EASE-Grid Sea Ice Motion Vectors, Version 2)
The NSIDC product are sea-ice motions deduced from a variety of satellite-borne sensors (Advanced Very High Resolution
Radiometer (AVHRR), Scanning Multichannel Microwave Radiometer (SMMR), SSM/I and AMSR-E, as
well as the International Arctic Buoy Program (IABP) observations and wind effects on motion. Sea-ice
motions are obtained from each satellite sensor using the MCC method and merged with the buoy data and
winds using the cokriging method.

Kimura, N. and M. Wakatsuchi (2004), Increase and decrease of sea ice area in the Sea of Okhotsk: Ice production
in coastal polynyas and dynamical thickening in convergence zones, Journal of Geophysical Research, 109, C09S03,
doi:10.1029/2003JC001901.

Snow depth

From a certain age onwards there is a snow layer on top of the sea ice. The difficulty to determine its thickness is
similar to the measurement of the sea ice thickness. Currently only few long-term data exists that is spatially
extensive and collected all year round. Due to the snow’s high capability to reflect solar radiation (albedo) and its
low thermal conductivity it is an important component of the superficial energy balance in the Arctic. Satellite
measurements and snow buoys collect data for the snow depth on sea ice in the Arctic and Antarctic.

On meereisportal.de the data on snow depth is compiled from snow buoys in the Arctic and Antarctica. Furthermore, the
monthly means from October to March are available for the Arctic since 2010. They are derived from CryoSat-2 data.

Multiyear ice

Sea ice in the Arctic can be classified into several types, the main ones being

young ice (YI): thin (up to 30 cm thick) new ice; includes a few sub-types; can be smooth or rough

first-year ice (FYI): formed during one cold season; thickness above 30 cm; surface can be level, rough or with ridges

multiyear ice (MYI): ice that has survived at least one melt season; less saline and often rougher than FYI, but topographic features are generally smoother than FYI

The physical properties of sea ice differ significantly for the different ice types. Therefore, knowledge of the sea ice type is important for
a number of activities including marine navigation and modelling of the ice-ocean-atmosphere system and also for remote sensing of other quantities
related to sea ice such as the depth of the snow layer on top of it. With the recent accelerated decrease of MYI in the Artic, mapping this ice type
on a daily basis has become important for many applications.

The MYI data on this site are from a new satellite-based retrieval of sea ice type in the Arctic which can in principle distinguish YI,
FYI and MYI. The retrieval method uses active and passive microwave data (radar scatterometer and radiometer, respectively). The former
are acquired by the sensor ASCAT on the Metop satellites. Until 2015, data regridded to the common 12.5 km North polar stereographic grid
(“NSIDC grid”) by Ifremer/CERSAT were taken. After that, near-real time ASCAT data were regridded by the University of Bremen
(Institute of Environmental Physics). The passive microwave data are from either AMSR-E on the Aqua satellite by NASA (until 2011) or from
AMSR2 on the GCOM-W1 satellite by JAXA (since 2012). More information about the retrieval method and the algorithm can be found here
(https://seaice.uni-bremen.de/multiyear-ice-concentration/information/).

Directly at the coast, the signal of the scatterometer or radiometer data can contain a contribution from the land, resulting in errors in the
MYI concentration. Therefore, during the first 10 days of the season (end of September) a zone that is one pixel wide, along all coasts, is
cleared of MYI unless connected to MYI offshore.

Finally, surface temperature data and sea ice drift data are used in several correction schemes which are applied to account for the effect
of melt-refreeze processes, snow metamorphosis and sea ice drift on the sea ice type retrieval. However, it should be noted that weather influence
on the surface of the MYI (including the snow cover) can be the reason for considerable day-to-day fluctuation of MYI concentration and in the Eastern
Arctic (Kara and Laptev Sea), unrealistically high MYI concentrations occur in March and April probably due to small areas of spurious MYI caused by
rough young ice (possible with wet snow) in the previous autumn. More information on the retrieval algorithm and the data sources can be found here
(https://seaice.uni-bremen.de/multiyear-ice-concentration/information/).

The Arctic multiyear sea ice data are available for the time period from 2012 until 2019 and are provided by the University of Bremen
(Institute of Environmental Physics). As the retrieval does not work during the melt season, the data record usually spans October to May.

Sea ice edge comparison

In order to make a comparative statement about the change in the sea ice concentration in different regions for different months and years,
the differences of the ice edges are shown on a map. For this purpose, the monthly
mean position of the ice edge (15% sea ice concentration) for the respective month of the year can be calculated from
the data of the sea ice concentration
of the University of Bremen (Institute of Environmental Physics).
Differences can then be queried for the long-term average (from 2003 to 2014) or for a monthly mean of the same month of any year. Thus, regions with a
sea ice gain (blue) and a sea ice take-off (red) become clearly visible.

Climatological data

The NCEP/NCAR Reanalysis data set is a continually updated globally gridded data set that represents the state of the Earth's atmosphere,
incorporating observations and numerical weather prediction (NWP) model output from 1948 to present. It is a joint product from the National
Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR). A large subset of this data is available
from PSD in its original 4 times daily format and as daily averages. The resolution of the global Reanalysis Model is T62 (209 km) with 28
vertical sigma levels. Results are available at 6 hour intervals. There are over 80 different variables, (including geopotential height,
temperature, relative humidity, u- and v- wind components, etc.) in several different coordinate systems, such as 17 pressure level stack
on 2.5 by 2.5 degree grids, 28 sigma level stack on 192 by 94 Gaussian grids, and 11 isentropic level stack on 2.5 by 2.5 degree grid.

Derived products

In addition to the directly measured parameters, there are also derived products,
which are important for the description of the condition of the sea ice. The derived sea ice products are therefore provided in this area of the
data portal. They can be selected from the top navigation bar.

Sea ice concentration

The data, maps and sea ice analyses of the Arctic available for download are based on the information
of the satellite radiometers mentioned below. Measurements of the satellite radiometer AMSR-E range from June 19th,
2002 until September 30th, 2011. On Oct 4, 2011, measurements of AMSR-E stopped.

AMSR-E‘s successor AMSR2 was successfully deployed to orbit on May 18th 2012. Since August 1st, 2012 AMSR2 has been
sending microwave data from which daily sea ice concentrations are derived. Sea ice concentration based on SSMIS has been available from
October 1st, 2011 up to today. Data of AMSR2 is of higher quality than SSMIS data. On meereisportal.de, SSMIS data is
therefore only used to fill data gaps of AMSR2. The sensor used to define sea ice concentrations is recorded in the
name of the respective daily file.

If there are any questions or difficulties, please do not hesitate to contact info@meereisportal.de.
We are pleased to help and steadily improve our offer.

Furthermore, downloads of daily updated KMZ files usable for Google Earth depictions are available for the
Arctic and
Antarctic.

Soon, also KMZ- and GeoTIFF-files will be available for download for the entire period via the selection menu.

Besides the daily data sets, monthly data sets can be downloaded as well. Development, validation and improvement of
the evaluating algorithms were performed in connection with the EU project DAMOCLES (Developing Arctic Modeling and
Observing Capabilities for Long-term Environmental Studies). Sea ice extent was determined by direct satellite
measurements and the so-called “ARTIST” sea ice algorithm. It has been used and validated in many scientific
studies.

We assume no liability for any of the provided data available for downloaded.

Sea ice concentration is represented in the maps by a uniform color scale: White represents a sea ice concentration
of 100%, dark blue marks the regions with the lowest sea ice concentration. According to standard definition , sea
ice extent is the continuous area for which a sea ice concentration of at least 15 % is measured.

All graphs need to be cited according to the rules listed in the "Terms of Use".

Sea ice edge comparison

In order to make a comparative statement about the change in the sea ice concentration in different regions for different months and years,
the differences of the ice edges are shown on a map. For this purpose, the actual position of the ice edge
(15% sea ice concentration)
for the respective day of the year can be calculated from
the data of the sea ice concentration
of the University of Bremen (Institute of Environmental Physics).
Differences can then be queried for the long-term average (from 2003 to 2014) or for a monthly mean of the same month of 2012. Thus, regions with a
sea ice gain (blue) and a sea ice take-off (red) become clearly visible.

Multi-Sensor Sea Ice Maps for MOSAiC

In order to assess the sea ice situation in the MOSAiC starting region, multiple types of information are required. This information is provided by satellite observations,
which record various sea ice parameters, allowing a better estimate of the sea ice situation in the area. The most important parameters include sea ice concentration,
ice drift and the general condition of the ice surface, and data on these are supplied by three different satellite products:

(SAR + Drift)

High-resolution satellite images (FramSat/Driftnoise.com, ESA)
The radar satellite images from
Sentinel-1 have a resolution of 50 m, making it possible to observe the characteristics of the sea ice surface in detail. However, due to ambiguities, the radar images
can’t always be clearly interpreted. Very dark areas (little backscattering) indicate either open water (in calm conditions) or young ice. Light, or very light areas
(a lot of backscattering) suggest that the surface is rough, which means either that there is older sea ice or that open sea has been stirred up by the wind. The degree
of backscattering allows conclusions to be drawn about the roughness of the surface. On closer examination, individual sea-ice floes and leads can be identified.

(Sea ice concentration + Drift)

Ice-concentration product AMSR-2 (AWI/JAXA)
Ice concentration, derived from data from the passive microwave radiometer AMSR2, indicates what percentage of the surface in a given area is covered by sea ice. This information, which is colour coded and displayed as semi-transparent areas on the map, is available with a resolution of 3 km. For more information on the sea ice concentration product, see the following paper:
Beitsch, A.; Kaleschke, L. and Kern, S. (2014), Investigating High-Resolution AMSR2 Sea Ice Concentrations during the February 2013 Fracture Event in the Beaufort Sea.
Remote Sensing, 6, 3841-3856, doi:10.3390/rs6053841.

(Sea ice concentration + SAR + Drift)

Ice drift product (OSI SAF)
Ice drift is estimated using a correlation method based on time-delayed satellite data. It shows the velocity at which the sea ice has moved over the last 48 hours.
The information is presented with vector arrows, which vary in length according to the speed and indicate the direction of ice movement.

In order to present all this information in real time and in a compressed form, an automatic service has been set up, which creates two daily maps.
1. One map showing the parameters of the three products for the previous day, superimposed over each other in the above order.
2. One map showing only the high-resolution satellite image superimposed with ice drift vectors.
Since high-resolution satellite images are not always available for the entire map section, the
coverage is irregular, and this is reflected in the figures. The section on the top right shows the location of the map detail in the Arctic.

Before the actual MOSAiC Drift begins, a daily map showing the likely starting region (grey box) will be created. As soon as the research vessel RV Polarstern enters
this area, her position there will be shown. Once a suitable ice floe has been found, the ice camp has been set up and the year-long drift has begun, the map section will
move along with the RV Polarstern.

Polarstern drift

The ship’s potential drift route can be roughly estimated in advance by reconstructing the course that the ice followed from the starting point in past years.
This involves the use of satellite data, which depicts the ice drift in the Arctic on a daily basis. The analytical tool used for the ice drift is called
IceTrack and was developed at the AWI. In addition to various types of satellite data
(ice drift,
ice concentration,
ice thickness), reanalysis data – which provides insights into temperature,
wind speed and atmospheric pressure in the Arctic – is taken into account. In this way, not only the ice drift in the past years can be reconstructed
for individual potential starting points, but all key atmospheric factors influencing the ice can also be included. A comprehensive description of these methods was
recently released in connection with a study that investigated changes in the Transpolar Drift as a result of global warming
(source: Nature).

The data portal displays drift scenarios for various potential starting points. Each figure shows the drift trajectories for the years 2005 – 2017 for
the respective starting point (e.g. 85°N / 130°E). For the purposes of the drift analysis, the starting date is always 1 October of the respective year. The ice’s
progress in the course of a year is reconstructed using the IceTrack algorithm, and the calculation is only stopped when the ice cover at the respective position
drops below a certain threshold (50 %), at which point we have to assume that the MOSAiC ice floe would have melted. The colours used for the trajectories symbolise
the month for the respective position. More information on the data can be found in the information part of seaiceportal.de
here.

Ship radar images of the last 14 days

Actual radar-image sequence of RV Polarstern from the last 14 days.
More videos can be found here.

Live stream from on board: The latest radar images of the ship’s surroundings

Every day, here at meereisportal.de we show from now on a video sequence of ship radar images. The RV Polarstern’s marine radar systems will continue to operate throughout
the drift phase and images produced by the system are transmitted to Bremerhaven several times a day. The imaging system, which shows Polarstern in the centre of the screen,
offers vital information on floe movements, deformation and formation of cracks in the ship’s immediate vicinity.

Radar Systems on the RV Polarstern:

(Foto: S. Hendricks)

Navigation at sea is facilitated by radar systems. In this regard, RV Polarstern is equipped with several marine radar systems, which are used to identify other ships and obstacles.
When moving through pack ice, these systems offer information on the presence of channels or massively deformed pack ice. The radar systems feature rotating antennas that are
mounted on the observation deck, above the bridge. The antennas transmit microwave pulses at short intervals, which are reflected back to the radar system by the water or pack ice.
This produces an image of the positions of ice floes within a radius of 3 nautical miles (ca. 5,4 km) and their sizes in relation to the ship. This imaging technique remains unaffected
by weather or darkness, i.e., it can penetrate rainclouds and fog, and offers an undiminished view at night (you can find more information on marine radar systems
here.
An example for a scientific application of a marine radar system to study sea ice deformation can be found
here.

The forecasts are based on mutiple systems from several operational forecast centres as well as research institutes. Every six hours we produce a seemless consensus forecast
(including uncertainties) out to 120 days ahead based on the forecasts currently available. The forecasts are made available to Polarstern‘s on-board charting system (MapViewer),
and can be accessed publicly as follows:

4) All consensus forecasts and individual forecasts, for Polarstern and for all other SIDFEx targets, can be accessed through the SIDFEx Webtool
https://sidfex.polarprediction.net/. The most recent forecasts are available under
the tab „Most recent forecast“, where a specific target time can be selected. The forecasts from various systems will be summarised in a table; clicking
on one of the rows will show additional details for the selected forecast on a map and in time series for latitude and longitude.

Ice Charts from National Ice Services

In order to support navigation in the ice and help plan research activities, not only satellite data, but also the ice charts provided by national ice services are essential.
These charts summarise the results of comprehensive analyses of satellite and model-based data, which are visually conducted by ice analysts. Throughout the MOSAiC expedition,
ice charts will be provided by the Arctic and Antarctic Research Institute in St Petersburg (AARI).
As a rule, new charts will be made available on this site every week or every two weeks, and are based on satellite and model data from the previous week. Analyses will be
prepared for the ice conditions in the direct vicinity of RV Polarstern, and for the routes used by her resupply icebreakers.

The ice information will be presented in keeping with the established international standard. You’ll find a detailed description of the information provided
here (source: WMO).
For more information on how these ice charts are prepared, please click
here.

Autonomous measurements of sea ice properties

Buoys, or more generally speaking "ice tethered platforms" that perform autonomous measurements of physical
properties of sea ice, snow, and the uppermost ocean are one of the main instruments to collect time-series data
sets from the remote polar regions. Here we present data, metadata, and results from our buoys drifting on Arctic
and Antarctic sea ice.

Other buoys

International Program on Antarctic Buoys (IPAB): https://www.ipab.aq/ (note that this page is currently under revision for
updates).

In addition, all data from active and past Sea Ice Mass-Balance Buoys, which are under administration of the Cold
Regions Research and Engineering Laboratory (CRREL) may be found here:
http://imb.erdc.dren.mil/newdata.htm

Note: If you are aware of other buoy data collections, please send us a message, we would be happy to link them here,
too.

It could be the largest-scale Arctic research expedition of all time: in September 2019 the German research icebreaker Polarstern will depart from Tromsø,
Norway and, once it has reached its destination, will spend the next year drifting through the Arctic Ocean, trapped in the ice. A total of 600 people from
19 countries, who will be supplied by other icebreakers and aircraft, will participate in the expedition – and several times that number of researchers will
subsequently use the data gathered to take climate and ecosystem research to the next level. The mission will be spearheaded by the Alfred Wegener Institute,
Helmholtz Centre for Polar and Marine Research (AWI). More information about the expedtion here.
Further map and data products around sea ice come up it soon.

For all CryoSat-2 data, please
1) include the following phrase into the acknowledgment:
Processing of the CryoSat-2 (PARAMETER) is funded by the German Ministry of Economics Affairs and Energy (grant: 50EE1008) and data from DATE to DATE obtained from https://www.meereisportal.de (grant: REKLIM-2013-04).
2) refer to: Ricker, R.; Hendricks, S.; Helm, V.; Skourup, H. and Davidson, M. (2014), Sensitivity of CryoSat-2 Arctic sea-ice freeboard and thickness on radar-waveform interpretation, The Cryosphere, 8 (4), 1607-1622, doi:10.5194/tc-8-1607-2014.

SMOS dataSMOS data

For all SMOS data, please
1) include the following phrase into the acknowledgment:
Processing of the SMOS Date (PARAMETER) was funded by EU project SIDARUS and data from DATE to DATE obtained from https://www.meereisportal.de (grant: REKLIM-2013-04).
2) refer to: Huntemann, M.; Heygster, G.; Kaleschke, L.; Krumpen, T.; Mäkynen, M. and Drusch, M. (2014): Empirical sea ice thickness retrieval during the freeze-up period from SMOS high incident angle observations, The Cryosphere, 8, 439-451, doi:10.5194/tc-8-439-2014.

CryoSat-2/SMOS dataCryoSat-2/SMOS data

For all CryoSat-2/SMOS data, please
1) include the following phrase into the acknowledgment:
The merging of CryoSat-2 und SMOS data was funded by the ESA project SMOS+ Sea Ice (4000101476/10/NL/CT and 4000112022/14/I-AM) and data from DATE to DATE were obtained from https://www.meereisportal.de (grant: REKLIM-2013-04).
2) refer to: Ricker, R.; Hendricks, S.; Kaleschke, L.; Tian-Kunze, X.; King, J. and Haas, C. (2017), A weekly Arctic sea-ice thickness data record from merged CryoSat-2 and SMOS satellite data, The Cryosphere, 11, 1607-1623, doi:10.5194/tc-11-1607-2017.